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An In Vitro Study
to Evaluate the Genotoxicity of Value Added Hydroxyapatite as a Bone
Replacement Material
(Kajian In Vitro untuk Menilai Genotoksisiti Hidroksiapatit Tambah Nilai sebagai Bahan
Tulang Gantian)
Akram Hassan
School of Dental Sciences, Universiti Sains Malaysia
16150 Kubang Kerian, Kelantan, Malaysia
Dasan Swaminathan*
Department of Oral Pathology, Oral Medicine and Periodontology
Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
Received: 3 March 2010 / Accepted: 9 June 2010
ABSTRACT
Hydroxyapatite (HA)
used for bone replacement is one of the most active areas of ceramic
biomaterials research currently. It has been used clinically for the last 20
years due to its excellent biocompatibility, osseoconduction and
osseointegration. Many modifications have been done to develop a stronger,
tougher and biocompatible ceramic biomaterial because pure HA is
brittle. Researchers in Universiti Sains Malaysia had developed this value
added HA that is stronger and less brittle compared to pure HA.
The objective of this in vitro study was to evaluate the
genotoxic characteristic of the value added HA based
material by using Bacterial Reverse Mutation Assay (Ames test). The Bacterial
Reverse Mutation Assay of HA was performed on Salmonella
typhimurium strains TA98, TA100, TA1535, TA1537 and Escherichia coli strain
WP2 uvrA using the preincubation method in the presence and absence of an
exogenous metabolic activation system. All the bacterial tester strains treated
with and without S9 Mix showed no increase of revertant colonies with increase
in concentration of test substance for both the dose finding test and the main
test. The number of revertant colonies was less than twice that of the solvent
control for all the five bacterial strains and this was reproducible for both
the dose finding test and the main test. The numbers of revertant colonies in
the negative and positive controls were within the background data of our
laboratory. In conclusion the results of the tests showed that the value added HA was
considered to have no reverse mutagenic potential under the present test
conditions.
Keywords: Ames test;
genotoxicity; hydroxyapatite
ABSTRAK
Hidroksiapatit (HA)
yang digunakan untuk tulang gantian merupakan salah satu daripada bidang
penyelidikan biobahan seramik yang paling aktif masa kini. Ia diguna secara
klinikal sejak 20 tahun dahulu disebabkan oleh sifatnya yang sangat baik
daripada sudut bioserasi, oseokonduksi dan oseointegrasi. Banyak pengubahsuaian
telah dilakukan untuk menghasilkan biobahan seramik yang lebih kuat, lebih
keras dan bioserasi disebabkan HA yang asli adalah rapuh.
Penyelidik Universiti Sains Malaysia telahpun menghasilkan HA tambah
nilai ini yang lebih kuat dan kurang rapuh berbanding dengan HA asli.
Tujuan kajian in vitro ini adalah untuk menilai sifat genotoksik bahan
berdasarkan HA tambah nilai dengan menggunakan ‘Bacterial Reverse
Mutation Assay’ (ujian Ames). ‘Bacterial Reverse Mutation Assay’ untuk HA ini
telah dilakukan ke atas Salmonella typhimurium strain TA98,
TA100, TA1535, TA1537 dan Escherichia coli strain WP2 uvrA dengan
menggunakan cara prainkubasi dengan kehadiran dan ketidakhadiran sistem
pengaktifan metabolik eksogenus. Kesemua strain bakteria yang diuji, yang
dirawat dengan atau tanpa ‘S9 Mix’ menunjukkan tiada pertambahan koloni
‘revertant’ dengan penambahan kepekatan bahan yang diuji untuk ujian pencarian
dos dan ujian utama. Jumlah bilangan koloni ‘revertant’ adalah berkurangan dua
kali ganda dengan kawalan pelarut untuk kesemua lima strain bakteria dan ini
adalah sama untuk kedua-dua ujian pencarian dos dan ujian utama. Jumlah
bilangan koloni ‘revertant’ untuk kawalan negatif dan positif adalah dalam lingkungan
data latar makmal. Kesimpulannya, keputusan daripada ujian-ujian menunjukkan HA tambah
nilai ini telah dianggap tiada potensi mutagenik berbalik dalam keadaan yang
diuji.
Kata kunci:
Genotoksisiti; hidroksiapatit; ujian Ames
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Akram
Hassan
*Corresponding author; email: dasans@um.edu.my
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